ui/app/src/main/java/com/luozi/fireeyewatcher/utils/Cache.java
package com.luozi.fireeyewatcher.utils;

import android.content.Context;
import android.os.Environment;
import android.text.TextUtils;
import android.util.Log;

import java.io.File;

public class Cache {
    /**
     * 获取应用专属缓存目录
     * android 4.4及以上系统不需要申请SD卡读写权限
     * 因此也不用考虑6.0系统动态申请SD卡读写权限问题，切随应用被卸载后自动清空 不会污染用户存储空间
     * @param context 上下文
     * @param type 文件夹类型 可以为空，为空则返回API得到的一级目录
     * @return 缓存文件夹 如果没有SD卡或SD卡有问题则返回内存缓存目录，否则优先返回SD卡缓存目录
     */
    public static File getCacheDirectory(Context context, String type) {
        File appCacheDir = getExternalCacheDirectory(context,type);
        if (appCacheDir == null){
            appCacheDir = getInternalCacheDirectory(context,type);
        }

        if (appCacheDir == null){
            Log.e("getCacheDirectory","getCacheDirectory fail ,the reason is mobile phone unknown exception !");
        }else {
            if (!appCacheDir.exists()&&!appCacheDir.mkdirs()){
                Log.e("getCacheDirectory","getCacheDirectory fail ,the reason is make directory fail !");
            }
        }
        return appCacheDir;
    }

    /**
     * 获取SD卡缓存目录
     * @param context 上下文
     * @param type 文件夹类型 如果为空则返回 /storage/emulated/0/Android/data/app_package_name/cache
     *             否则返回对应类型的文件夹如Environment.DIRECTORY_PICTURES 对应的文件夹为 .../data/app_package_name/files/Pictures
     * {@link android.os.Environment#DIRECTORY_MUSIC},
     * {@link android.os.Environment#DIRECTORY_PODCASTS},
     * {@link android.os.Environment#DIRECTORY_RINGTONES},
     * {@link android.os.Environment#DIRECTORY_ALARMS},
     * {@link android.os.Environment#DIRECTORY_NOTIFICATIONS},
     * {@link android.os.Environment#DIRECTORY_PICTURES}, or
     * {@link android.os.Environment#DIRECTORY_MOVIES}.or 自定义文件夹名称
     * @return 缓存目录文件夹 或 null（无SD卡或SD卡挂载失败）
     */
    public static File getExternalCacheDirectory(Context context,String type) {
        File appCacheDir = null;
        if( Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
            if (TextUtils.isEmpty(type)){
                appCacheDir = context.getExternalCacheDir();
            }else {
                appCacheDir = context.getExternalFilesDir(type);
            }

            if (appCacheDir == null){// 有些手机需要通过自定义目录
                appCacheDir = new File(Environment.getExternalStorageDirectory(),"Android/data/"+context.getPackageName()+"/cache/"+type);
            }

            if (appCacheDir == null){
                Log.e("getExternalDirectory","getExternalDirectory fail ,the reason is sdCard unknown exception !");
            }else {
                if (!appCacheDir.exists()&&!appCacheDir.mkdirs()){
                    Log.e("getExternalDirectory","getExternalDirectory fail ,the reason is make directory fail !");
                }
            }
        }else {
            Log.e("getExternalDirectory","getExternalDirectory fail ,the reason is sdCard nonexistence or sdCard mount fail !");
        }
        return appCacheDir;
    }

    /**
     * 获取内存缓存目录
     * @param type 子目录，可以为空，为空直接返回一级目录
     * @return 缓存目录文件夹 或 null（创建目录文件失败）
     * 注：该方法获取的目录是能供当前应用自己使用，外部应用没有读写权限，如 系统相机应用
     */
    public static File getInternalCacheDirectory(Context context,String type) {
        File appCacheDir = null;
        if (TextUtils.isEmpty(type)){
            appCacheDir = context.getCacheDir();// /data/data/app_package_name/cache
        }else {
            appCacheDir = new File(context.getFilesDir(),type);// /data/data/app_package_name/files/type
        }

        if (!appCacheDir.exists()&&!appCacheDir.mkdirs()){
            Log.e("getInternalDirectory","getInternalDirectory fail ,the reason is make directory fail !");
        }
        return appCacheDir;
    }
}
